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1.
Muscle hypertrophy and fast fiber type conversions in heavy resistance-trained women 总被引:1,自引:0,他引:1
R. S. Staron E. S. Malicky M. J. Leonardi J. E. Falkel F. C. Hagerman G. A. Dudley 《European journal of applied physiology and occupational physiology》1990,60(1):71-79
Twenty-four women completed a 20-week heavy-resistance weight training program for the lower extremity. Workouts were twice a week and consisted of warm-up exercises followed by three sets each of full squats, vertical leg presses, leg extensions, and leg curls. All exercises were performed to failure using 6-8 RM (repetition maximum). Weight training caused a significant increase in maximal isotonic strength (1 RM) for each exercise. After training, there was a decrease in body fat percentage (p less than 0.05), and an increase in lean body mass (p less than 0.05) with no overall change in thigh girth. Biopsies were obtained before and after training from the superficial portion of the vastus lateralis muscle. Sections were prepared for histological and histochemical examination. Six fiber types (I, IC, IIC, IIA, IIAB, and IIB) were distinguished following routine myofibrillar adenosine triphosphatase histochemistry. Areas were determined for fiber types I, IIA, and IIAB + IIB. The heavy-resistance training resulted in significant hypertrophy of all three groups: I (15%), IIA (45%), and IIAB + IIB (57%). These data are similar to those in men and suggest considerable hypertrophy of all major fiber types is also possible in women if exercise intensity and duration are sufficient. In addition, the training resulted in a significant decrease in the percentage of IIB with a concomitant increase in IIA fibers, suggesting that strength training may lead to fiber conversions. 相似文献
2.
The level of topoisomerase I mRNA was measured in cells of two mouse lymphoma (LY) sublines treated with db-cAMP. A transient increase of the level was observed to be of about 60% of the basic level and to have maximum after the 3 h treatment of LY-S cells. The increase in LY-R subline was two-fold lower. The activity of PKA in a cytosol fraction of LY-S cells was 1.75 times higher than that in LY-R cells. The activity of PKA in membranes and nuclear fraction did not differ significantly in both cell types. When the activity of PKA in LY-S cells was inhibited with H8, no increase of the level of topoisomerase I mRNA was observed upon db-cAMP treatment of cells. We suggest that the activity of PKA in the cytosol controls the expression of topoisomerase I gene in LY cells at high concentration of cAMP.Abbreviations db-cAMP
dibutyryl-cAMP
- H8
N-[2-(methylamino)ethyl]-5-isoquinolinesulfonamide
- LY
mouse L5178Y lymphoma
- PKA
protein kinase A
- topo I
topoisomerase I 相似文献
3.
Effects of sprint cycle training on human skeletal muscle 总被引:3,自引:0,他引:3
Allemeier C. A.; Fry A. C.; Johnson P.; Hikida R. S.; Hagerman F. C.; Staron R. S. 《Journal of applied physiology》1994,77(5):2385-2390
4.
5.
Adult pigeons received dantrolene sodium, a skeletal muscle relaxant which blocks the release of calcium during excitation-contraction coupling, for 12 to 16 weeks. The pectoralis muscles of these birds were analyzed for changes occurring in the various fiber types of the muscle. Both histochemistry (ATPase and SDH activity) and electron microscopy (mitochondrial and lipid volume percentages) differentiated two fiber types. The two fiber-types consisted of fast-twitch glycolytic fibers (FG) and fast-twitch oxidative-glycolytic (FOG) fibers. After dantrolene treatment some FG fibers showed little or no ATPase activity. Dantrolene treatment also produced a disappearance of thick filaments in some FG fibers. We infer that the fibers without thick filaments are the ones lacking ATPase activity. The FOG fibers were nearly normal. Since drug-fed birds lose weight, a few birds were starved to determine whether the filament loss was related solely to the bird's loss in weight. No fibers in starved birds showed reduced ATPase activity or loss of thick filaments. In fibers that showed thick filament disappearance, the I-bands remained organized and intact, suggesting that the I-band maintains its integrity without interaction with the thick filaments. Changes in activity patterns may cause loss of thick filaments by inhibiting either their synthesis or assembly. 相似文献
6.
Agnieszka Girstun Takao Ishikawa Krzysztof Staron 《Journal of cellular biochemistry》2019,120(7):11794-11808
Subnuclear localization of topoisomerase I (top I) is determined by its DNA relaxation activity and a net of its interactions with in majority unidentified nucleolar and nucleoplasmic elements. Here, we recognized SR protein SRSF1 (Serine/arginine-rich splicing factor 1, previously known as SF2/ASF) as a new element of the net. In HeLa cells, overexpression of SRSF1 recruited top I to the nucleoplasm whereas its silencing concentrated it in the nucleolus. Effect of SRSF1 was independent of top I relaxation activity and was the best pronounced for the mutant inactive in relaxation reaction. In HCT116 cells where top I was not released from the nucleolus upon halting relaxation activity, it was also not relocated by elevated level of SRSF1. Out of remaining SR proteins, SRSF5, SRSF7, and SRSF9 did not influence the localization of top I in HeLa cells whereas overexpression of SRSF2, SRSF3, SRSF6, and partly SRSF4 concentrated top I in the nucleolus, most possibly due to the reduction of the SRSF1 accessibility. Specific effect of SRSF1 was exerted because of its distinct RS domain. Silencing of SRSF1 compensated the deletion of the top I N-terminal region, individually responsible for nucleoplasmic localization of the mutant, and restored the wild-type phenotype of deletion mutant localization. SRSF1 was essential for the camptothecin-induced clearance from the nucleolus. These results suggest a possible role of SRSF1 in establishing partition of top I between the nucleolus and the nucleoplasm in some cell types with distinct combinations of SR proteins levels. 相似文献
7.
Large, rapidly evolving intergenic spacers in the mitochondrial DNA of the salamander family Ambystomatidae (Amphibia: Caudata) 总被引:3,自引:2,他引:3
We report the presence, in the mitochondrial DNA (mtDNA) of all of the
sexual species of the salamander family Ambystomatidae, of a shared 240- bp
intergenic spacer between tRNAThr and tRNAPro. We place the intergenic
spacer in context by presenting the sequence of 1,746 bp of mtDNA from
Ambystoma tigrinum tigrinum, describe the nucleotide composition of the
intergenic spacer in all of the species of Ambystomatidae, and compare it
to other coding and noncoding regions of Ambystoma and several other
vertebrate mtDNAs. The nucleotide substitution rate of the intergenic
spacer is approximately three times faster than the substitution rate of
the control region, as shown by comparisons among six Ambystoma
macrodactylum sequences and eight members of the Ambystoma tigrinum
complex. We also found additional inserts within the intergenic spacers of
five species that varied from 87-444 bp in length. The presence of the
intergenic spacer in all sexual species of Ambystomatidae suggests that it
arose at least 20 MYA and has been a stable component of the ambystomatid
mtDNA ever since. As such, it represents one of the few examples of a large
and persistent intergenic spacer in the mtDNA of any vertebrate clade.
相似文献
8.
Tomas ML Eagan Esteban C Gabazza Corina D’Alessandro-Gabazza Paloma Gil-Bernabe Shinya Aoki Jon A Hardie Per S Bakke Peter D Wagner 《Respiratory research》2012,13(1):48
Background
Systemic inflammation may contribute to cachexia in patients with chronic obstructive pulmonary disease (COPD). In this longitudinal study we assessed the association between circulating C-reactive protein (CRP), tumor necrosis factor (TNF)-α, interleukin (IL)-1ß, and IL-6 levels and subsequent loss of fat free mass and fat mass in more than 400 COPD patients over three years.Methods
The patients, aged 40–76, GOLD stage II-IV, were enrolled in 2006/07, and followed annually. Fat free mass and fat mass indexes (FFMI & FMI) were calculated using bioelectrical impedance, and CRP, TNF-α, IL-1ß, and IL-6 were measured using enzyme immunoassays. Associations with mean change in FFMI and FMI of the four inflammatory plasma markers, sex, age, smoking, FEV1, inhaled steroids, arterial hypoxemia, and Charlson comorbidity score were analyzed with linear mixed models.Results
At baseline, only CRP was significantly (but weakly) associated with FFMI (r = 0.18, p < 0.01) and FMI (r = 0.27, p < 0.01). Univariately, higher age, lower FEV1, and use of beta2-agonists were the only significant predictors of decline in FFMI, whereas smoking, hypoxemia, Charlson score, and use of inhaled steroids predicted increased loss in FMI. Multivariately, high levels of TNF-α (but not CRP, IL-1ß or IL-6) significantly predicted loss of FFMI, however only in patients with established cachexia at entry.Conclusion
This study does not support the hypothesis that systemic inflammation is the cause of accelerated loss of fat free mass in COPD patients, but suggests a role for TNF-α in already cachectic COPD patients. 相似文献9.
Differential response of cycling and noncycling cells to inducers of DNA synthesis and mitosis 总被引:1,自引:0,他引:1 下载免费PDF全文
The objective of this study was to determine whether cells in G(0) phase are functionally distinct from those in G(1) with regard to their ability to respond to the inducers of DNA synthesis and to retard the cell cycle traverse of the G(2) component after fusion. Synchronized populations of HeLa cells in G(1) and human diploid fibroblasts in G(1) and G(0) phases were separately fused using UV-inactivated Sendai virus with HeLa cells prelabeled with [(3)H]ThdR and synchronized in S or G(2) phases. The kinetics of initiation of DNA synthesis in the nuclei of G(0) and G(1) cells residing in G(0)/S and G(1)/S dikaryons, respectively, were studied as a function of time after fusion. In the G(0)/G(2) and G(1)/G(2) fusions, the rate of entry into mitosis of the heterophasic binucleate cells was monitored in the presence of Colcemid. The effects of protein synthesis inhibition in the G(1) cells, and the UV irradiation of G(0) cells before fusion, on the rate of entry of the G(2) component into mitosis were also studied. The results of this study indicate that DNA synthesis can be induced in G(0)nuclei after fusion between G(0)- and S-phase cells, but G(0) nuclei are much slower than G(1) nuclei in responding to the inducers of DNA synthesis because the chromatin of G(0) cells is more condensed than it is in G(1) cells. A more interesting observation resulting from this study is that G(0) cells is more condensed than it is in G(1) cells. A more interesting observation resulting from this study is that G(0) cells differ from G(1) cells with regard to their effects on the cell cycle progression of the G(2) nucleus into mitosis. This difference between G(0) and G(1) cells appears to depend on certain factors, probably nonhistone proteins, present in G(1) cells but absent in G(0) cells. These factors can be induced in G(0) cells by UV irradiation and inhibited in G(1) cells by cycloheximide treatment. 相似文献
10.
Staron RS Kraemer WJ Hikida RS Fry AC Murray JD Campos GE 《Histochemistry and cell biology》1999,111(2):117-123
The limb and trunk muscles of adult rats express four myosin heavy chain (MHC) isoforms, one slow (MHCI) and three fast (MHCIIa,
MHCIId, and MHCIIb). The distribution of these isoforms correlates with fiber types delineated using myofibrillar actomyosin
adenosine triphosphatase (mATPase) histochemistry. For example, type I fibers express MHCI and fiber types IIA, IID, and IIB
express MHCIIa, MHCIId, and MHCIIb, respectively. Fibers containing only one MHC isoform have been termed ”pure” fibers. Recent
evidence suggests that a population of ”hybrid” fibers exist in rat skeletal muscle which contain two MHC isoforms. The purpose
of the present investigation was to document the entire range of histochemically defined ”pure” and ”hybrid” fiber types in
untreated muscles of the young adult Fisher 344 rat hindlimb. The selected hindlimb muscles (soleus, tibialis anterior, extensor
digitorum longus, and gastrocnemius muscles) were removed from 12 male rats and analyzed for muscle fiber type distribution,
cross-sectional area, and MHC content. Care was taken to delineate eight fiber types (I, IC, IIC, IIA, IIAD, IID, IIDB, and
IIB) using refined histochemical techniques. Hybrid fibers were found to make up a considerable portion of the muscles examined
(a range of 8.8–17.8% of the total). The deep red portion of the gastrocnemius muscle contained the largest number of hybrid
fibers, most of which were the fast types IIAD (8.5±2.8%) and IIDB (5.2±2.3%). In conclusion, hybrid fibers make up a considerable
portion of normal rat limb musculature and are an important population that should not be ignored.
Accepted: 15 October 1998 相似文献